Connection block terminal



A. R. KUHN CONNECTION BLOCK TERMINAL March 7,' 1939.

Filed April 4, 1935 n 5 m E P tv m4 .m 7 1/ 1/ m .0 M 2m a 1 a. o V bx 7 2? a A 55M Patented 1, 1939 PATENT OFFICE common BLOCK TERMINAL Alfred B. Kuhn, Queens Village, N. Y., assignor to Metropolitan Device Corporation; Brooklyn, N. Y., a corporation of New York Application April 4, 1935, Serial No. 14,722

2 Claims. (C'l. 173 324) This invention relates to electrical apparatus provided with terminals-for the attachment of cables, such as connection blocks, switch blocks, fuse blocks and the like. In a specific application of the invention it relates to a connection block providing for the ready making and breaking of a circuit (for meter testing for example). with a minimum of resistance and at the same time with secure connections to the cables. The invention also relates to terminals which are peculiarly adapted as elements of connection blocks and the like for receiving cable ends.

A terminal of the clamp type is preferable to a soldered one as the serious objections of heatin required to make a soldered connection, limited heat resistance and relatively high current resistance are thereby avoided. With the clamp type of terminal, however, a tight grip on the cable which will not loosen with vibration is go essential.

the clamp type adapted for connection blocksand the like which is economically constructed yet rugged and suitable for securing cables of 5 relatively large size. In brief the terminal has for its dominant feature concentrated pressure contact or bearing areas for firmly gripping a cable without loosening. This is obtained by providing a terminal for a bar fitting, the terminal having an opening to receive the cable end and having as a part thereof a threaded stud on which is movably mounted a clamping member that is guided and held from turning by the terminal and means coacting with the stud for forcing the clamping member edges against the cable end. Fln'ther accentuation and concentration'of pressure can be obtained by a kink or wave formed in the cable-contact'surface on the bar and/or conforming the clamping member edges to the cross section of the cable end. The

bar which is so provided with a terminal formed with a threaded studand cable receiving opening can be a current-carrying bus bar or the equivalent of a connection block or other piece of electrical apparatus.

Fig. 1 illustrates in perspective an upstanding end member forming part of the terminal;

Fig. 2 is a perspective view of a bus bar construction for engaging the end member of Fig. 1;

Fig. 3 shows in perspective a modification of the bus bar of Fig. 2;

Fig. 4 is a horizontal cross sectional view on the line 4-4 of the end member of Fig. 1 with the bus bar of Fig. 3' inserted and projecting lo shoulders headed over;

contact the. flat portion to: of the terminal and cavity in the bus bar; 5

Fig. 6 is a view in perspective of a clamping member for mounting on the terminal end member of Fig. 1;

Fig. 7 is a perspective view of a nut for engaging the threaded stud of the end member to force 10 the clamping member into gripping contact with acable end; I

Fig. 8 is a view in vertical cross section of a. connection block showing the parts in assembled relation and securing a cable; and 15 Fig. 9 is a plan view of a block showing an assembly of separable'terminal end members on a single conductive bar-fitting.

The terminal comprises a bus bar I00 with a v separable upstanding end member for engaging 20 the end "II of the bus bar and provided with an 'opening for receiving a cable; theyupstanding 103. It is slotted as at I04 thus forming a yoke to receive an extended end or tongue I05 of the bar. A cable-receiving opening I06 can be formed as an extension of the slot. The bar nt- 30 the terminal I00 can be given a-modified end formation as shown in Fig. 3. In this formation the reducedend IIO provides shoulders III to 45 also with additional shoulders II2 forming a iurther contracted end II3.' In assembling the end H3 is inserted in the slot I04 and the shoulders H2 swaged or headed over as shown in Fig.

4 to securely hold the terminal to the bar fitting. The cable receiving surface II4 can be knurled as at II5 to give an increased gripping action. The terminal I00 can be further secured to the bar fitting by providing the under surface of the bar with a cavity I I0 and pressing the cross piece I" of the terminal into the cavity.

The assembly illustrated in Fig. 8 provides a connection block having a base I of insulating material. On the base there is mounted the bus shaped clamping member I33, shown in perspective in Fig. 6, has an opening I" for freely en- 'gaging the stud I03. The clamping member is made partly cylindrical to accommodate the stud, and the cable-engaging ends can be curved as I30, I or otherwise shaped to contact a cable. A threaded nut I 31 engages the stud for operating the clamping member.

A cable I40 that is to be clamped to the terminal has its insulating cover removed for a distance to expose the conducting strands Ill. The exposed strands are inserted in the opening I06 and the'nut I is turned to press the clamp into tight contact with the conductor; The clamp forces the cable against the bearing surface I08 of the bar at one side'and against the extension lll at the other side ,01 the member I00. In

order to position the cable in the connector.

block a screw I 3| can be extended to provide a stop I42. By these means the cable is positioned and then firmly secured by clamping on both sides of the yoke portion I02 of the member I00 to furnish a concentrated grip sufiiciently strong to sustain the weight of the cable when suspended as a vertical riser in a raceway.

The fiat portion I02 of the upstanding memher, in addition to receiving a cable conductor, can be given the function of serving as a guide for the clamping member I03 to prevent its turning by shaping the clamping member was to contact the sides of the bar. This construction insures an effective grip upon the cable as there is no rotation or sliding of the member over the cable surface. stud III also supplies a convenient means for The integrally formed additional temporary or permanent connections" such as those used-for taps to a main or for a meter tester.

More than one separable terminal can be secured to a bar fitting. This is illustrated in Fig.

9 where six separable terminals are attached to one fitting I20. Such a fitting can be attached to a block or other apparatus by screws I2'I for example,. which screws also form stops for the cable ends.

While the preferred forms of the invention have been illustrated, it is to be understood that other modifications can be made and that accordinglyno restriction on the invention is intended except as defined in the following claims.

What is claimed is: v

1. Terminal for receiving a cable comprising in combination a bar fitting having a perforation therethrough for a cable, a U-shaped clamping member embracing the fiat sides of the bar fitting and coacting with said fitting to provide ends for gripping a cable inserted through said perforation, d clamping member being guided against E21: by its engagement with the sides of the fit means for operating the clamping member, a bar approximately at right angles to the fitting, and means'securing said bar to the fitting, said means including a slot in one of the two elements and a tongue on the other extendi into the slot.

2. Terminal for receiving a cable comprising member, a bar approximately at right angles to the fitting. and means securing said-bar to thefitting, said means including a slot forming a continuation of the perforation in the fitting and a tongue on the bar extending into the slot.

- ALFRED R. KUHN. 

